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Explain Files & its Basics

File modes

Writing data to a file & reading data from a file

Explain File copy

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A Stream is generally referred to flow of data.

Different streams are used to represent different kinds of data flow

Each stream is associated with particular class which contains

member functions and definitions for dealing with that particular kind

of data flow

The sequence of input bytes are called as Input Stream

The sequence of output bytes are called as Output Stream

The cin object with >>operator is used for getting input

The cout object with

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ios

istream ostream

iostream

fstreamifstream ofstream

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The Header File contains the definitions for filestream classes

It contain the definitions for three classes. They are

1) ifstream

2) ofstream

3) fstream

Ofstream :

Every object of type ofstream uses a filename to storeinformation in that file.

Ifstream :To read the contents from a file we must create an object of

class ifstream.

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Opening a File

The Open() function is used to open different files that uses thesame stream object.

Syntax : open(filename, file mode);File Mode Description

ios :: in Open file for reading

ios :: out Open file for writing

ios :: app Open file for reading and/or writing the data atthe end of file (append)

ios :: ate Erase the file before reading or

writing(Truncated)ios :: nocreate Error when opening, if file does not already

exists

ios :: no replace Error when opening, if file does not alreadyexists, unless ate or app is set

ios :: binary Open file in binary mode (not text mode)

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Closing a File

To close a file, the member function close() must be used. It takesno parameters and returns no value.

Syntax : close();

Detecting End-Of-File

It is necessary for preventing any attempt to read data from thefile.

Syntax : eof()

put() and get() functions :

put() function displays a single character on the screen.

Syntax : put(char);

get() function gets a single character from the file

Syntax : get(void)

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#include

#include

#includevoid main()

{

ofstream outfile;

char fname[20];

cout

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#include#include

#include#includevoid main(){ifstream infile;

char fname[20];char ch;coutfname;

infile.open(fname);if(infile.fail()){cout

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#include#include

#include#includevoid main(){ofstream outfile;ifstream infile;

char source[10],target[10],ch ;clrscr();coutsource;couttarget;infile.open(source);if(infile.fail()){cout

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The getline() and write() functions

These two functions are line oriented input and output functions

respectively.

getline() function reads a complete line until it encounters a

newline character.

Syntax : cin.getline(char*,size);

Char* holds the inputline

Size The number of characters to be read

write Function

It is used for displaying a text in a line until it encounters a \n

characters.

Syntax : cout.write(char*,size);

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getline() and write() function Example

#include#includevoid main(){char name[50];clrscr();

Cout

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A stream is generally referred to a flow of data.

Each stream is associated with a particular class which contains

member functions and definitions for dealing with that particular

kind of data flow

The sequence of input bytes are called Input stream

The sequence of output bytes are called as output stream

The Ofstream is used for writing information to a file

The ifstream class is used for reading information from a file

The stream class is used for both writing and reading from a file